Wyniki wyszukiwania - BazTech

1

SHaPe: A Honeypot for Electric Power Substation

Kołtyś K., Gajewski R.

Journal of Telecommunications and Information Technology

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2015

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nr 4

37--43

EN

Supervisory Control and Data Acquisition (SCADA) systems play a crucial role in national critical infrastructures, and any failure may result in severe damages. Initially SCADA networks were separated from other networks and used proprietary communications protocols that were well known only to the device manufacturers. At that time such isolation and obscurity ensured an acceptable security level. Nowadays, modern SCADA systems usually have direct or indirect Internet connection, use open protocols and commercial-off-the-shelf hardware and software. This trend is also noticeable in the power industry. Present substation automation systems (SASs) go beyond traditional SCADA and employ many solutions derived from Information and Communications Technology (ICT). As a result electric power substations have become more vulnerable for cybersecurity attacks and they need ICT security mechanisms adaptation. This paper shows the SCADA honeypot that allows detecting unauthorized or illicit trac in SAS which communication architecture is dened according to the IEC 61850 standard.

2

Auction Models Supporting End-to-End Connection Trading

Kołtyś K., Pieńkosz K., Toczyłowski E.

Journal of Telecommunications and Information Technology

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2012

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nr 2

55-62

EN

The paper concerns bandwidth allocation problem on the telecommunication market where there are many sellers and buyers. Sellers offer the bandwidth of telecommunication links. Buyers are interested in the purchase of the bandwidth of several links that makes up an end-to-end connection between two nodes of telecommunication network. We analyze three auction models supporting such a bandwidth exchange: NSP (network second price), BCBT (model for balancing communication bandwidth trading) and BCBT-CG which is a modification of BCBT that applies column generation technique. All of these models concern divisible network resources, treat bandwidth of telecommunication links as an elementary commodity offered for sale, and allow for purchasing bandwidth along multiple paths joining two telecommunication nodes. All of them also aim at maximizing the social welfare. Considered auction models have been compared in the respect of economic and computational efficiency. Experimental studies have been performed on several test instances based on the SNDlib library data sets.

3

Bandwidth Trading: A Comparison of the Combinatorial and Multicommodity Approach

Kołtyś K., Pałka P., Toczyłowski E., Żółtowska I.

Journal of Telecommunications and Information Technology

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2010

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nr 2

67-72

EN

Since the telecommunication market becomes more complex and dynamic, a strong need for a new, efficient and flexible bandwidth trading mechanisms appears. We believe that good mechanisms, that allow effective and fair allocation of bandwidth between market participants will help to develop the real competitive bandwidth market. In this paper we compare two different double-sided bandwidth auction mechanisms, that seem to be well suited approaches for trading indivisible units of bandwidth: combinatorial auction c-SeBiDA and multicommodity mechanism BACBR-I. The c-SeBiDA mechanism considers two types of commodities: inter-node links and paths consisting of particular links. Market participants may bid a single link, or a bundle of links, constituting a specific path. The BACBR-I mechanism is a multicommodity exchange model, that allows bidders to place buy offers not only for individual or bundled links, but rather for end-to-end connections. Therefore, it is the decision model that allocates the most efficient links to connections. We run a large set of experiments to test the allocation and computational efficiency obtained under both approaches.

4

Model for Balancing Aggregated Communication Bandwidth Resources

Pałka P., Kołtyś K., Toczyłowski E., Żółtowska I.

Journal of Telecommunications and Information Technology

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2009

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nr 3

43-49

EN

In this paper we present a multicommodity bandwidth exchange model for balancing aggregated communication bandwidth resources (BACBR) that allows us to aggregate similar offers. In this model offers submitted to sell (or buy) the same, similar, or equivalent network resources (or demands for end-to-end connections) are aggregated into single commodities. BACBR model is based on the balancing communication bandwidth trade (BCBT) model. It requires much less variables and constraints then original BCBT, however the outcomes need to be disaggregated. The general model for disaggregation is also given in the paper.

5

Multicommodity Auction Model for Indivisible Network Resource Allocation

Kołtyś K., Pałka P., Toczyłowski E., Żołtowska I.

Journal of Telecommunications and Information Technology

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2008

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nr 4

60-66

EN

In this paper we present the multicommodity auction model BCBT-I that allocates indivisible network resources among bidders. The approach can be considered as a generalization of the basic multicommodity model for balancing communication bandwidth trade (BCBT). The BCBT model assumes that offers concerning inter-node links and point-to-point bandwidth demands can be realized partially. However, in the real-world trade there might be a need to include capacity modularity in the market balancing process. Thus we state the model for balancing communication bandwidth trade that takes into account the indivisibility of traded bandwidth modules. This requires to solve a mixed integer problem and increases computational complexity. Furthermore, the pricing issue appears nontrivial, as the dual prices cannot be longer used to set fair, competitive market prices. For clearing the market, we examine the multicommodity pricing mechanizm based on differentiation of buy and sell market prices.